ESD protection device with breakdown voltage stabilization

ABSTRACT

An electronic device includes a silicon-on-insulator (SOI) structure, and an electrostatic discharge (ESD) protection device, with an isolation layer having a thickness and extending in a trench from a first implanted region. The ESD protection device includes a conductive field plate that extends over a portion of the first implanted region and past the first implanted region and over a portion of the isolation layer by an overlap distance that is 3.5 to 5.0 times the thickness of the isolation layer. In one example, the ESD protection device has a finger or racetrack shape, and the first implanted region and a second implanted region extend around first and second turn portions of the finger shape.

BACKGROUND

Electrostatic discharge (ESD) events can be triggered by humaninteraction with a circuit board or an included electronic device, suchas an integrated circuit (IC), causing high voltages on one or more padsof the IC. If the IC is unprotected, the high pad voltage can lead toundesired current flow through internal circuitry, which can damage ordegrade circuit components of the IC. Accordingly, many ICs includeprotection devices or circuits to provide discharge paths between one ormore pads and a ground terminal, power terminal, or other referencenode. ESD protection devices or circuits may be provided to protectpower supply terminals, as well as to protect I/O terminals and otherexternal connections that may be subjected to ESD events. Ideally, thebreakdown voltage (BV) rating or triggering threshold of an ESDprotection device is tailored to the voltage rating of the protectedcircuitry and is stable for different operating conditions of theelectronic device. Early latch-up of ESD protection devices is desiredas it lowers silicon temperature and enhances current conduction. Nonuniform latch-up can lead to creation of hot spots, very low ESD ratingand poor reliability. However, the lower or handle substrate of an ICmade from a silicon-on-insulator (SOI) starting structure may be biasedrelative to the top side during operation, which can lead to breakdownvoltage variation. In addition, ESD protection devices operate andconduct max current in latch-up in response to ESD events that meet orexceed the breakdown voltage. A high ESD current rating is desired toreduce the size and cost of an ESD protected product, but a bias voltageon the handle substrate can lower the ESD current rating.

SUMMARY

An electronic device with an SOI structure includes an ESD protectiondevice, with an isolation layer that extends in a trench from a firstimplanted region. The ESD protection device includes a field plate thatextends over a portion of the first implanted region past the firstimplanted region and over a portion of the isolation layer by an overlapdistance that is tailored to the thickness of the isolation layer tomitigate breakdown voltage variation with handle substrate biasing. Inone example, the ESD protection device has a finger or racetrack shape,where the first implanted region and a second implanted region extendaround first and second turn portions of the finger shape. In oneexample, the ESD protection device includes a second isolation layerthat extends in the first implanted region, spaced apart from the firstisolation layer, and having a length along the first direction tailoredto mitigate ESD current rating degradation.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a partial sectional side elevation view of an integratedcircuit (IC) electronic device with a silicon controlled rectifier (SCR)ESD protection device.

FIG. 2 is a partial sectional top plan view of the SCR ESD protectiondevice taken along line 2-2 in FIG. 1.

FIG. 3 is a flow diagram of a method for making an ESD protection devicein an integrated circuit.

FIGS. 4-15 are partial sectional side elevation views of the electronicdevice of FIG. 1 at different stages of fabrication according to themethod of FIG. 3.

FIG. 16 is a partial sectional side elevation view of another IC with aPNP bipolar transistor ESD protection device.

FIG. 17 is a partial sectional top plan view of the PNP ESD protectiondevice taken along line 17-17 in FIG. 16.

FIG. 18 is a partial sectional side elevation view of another IC with anNPN bipolar transistor ESD protection device.

FIG. 19 is a partial sectional top plan view of the NPN ESD protectiondevice taken along line 19-19 in FIG. 18.

FIG. 20 is a graph that shows comparative protection device center andedge breakdown voltage variation for different substrate voltages in anSOI-based ESD protection device.

FIG. 21 is a partial sectional side elevation view of electric potentiallines in a portion of the PNP ESD protection device of FIGS. 16 and 17with a first polysilicon field plate/shallow trench isolation (STI)overlap distance and a zero substrate voltage.

FIG. 22 is a partial sectional side elevation view of electric potentiallines a portion of the PNP ESD protection device of FIG. 20 with apositive non-zero substrate voltage.

FIG. 23 is a partial sectional side elevation view of electric potentiallines in a portion of the PNP ESD protection device of FIGS. 17 and 18with a longer second polysilicon/STI overlap distance and a zerosubstrate voltage.

FIG. 24 is a partial sectional side elevation view of electric potentiallines a portion of the PNP ESD protection device of FIG. 22 with thepositive non-zero substrate voltage.

FIG. 25 is a partial sectional side elevation view of electric fieldstrength regions in a portion of the PNP ESD protection device of FIGS.23 and 24 with the second polysilicon/STI overlap distance and thepositive non-zero substrate voltage.

FIG. 26 is a partial sectional side elevation view of electric fieldstrength regions in a portion of the PNP ESD protection device with astill longer third polysilicon/STI overlap distance and the positivenon-zero substrate voltage.

FIG. 27 is a partial sectional side elevation view of an example of theNPN ESD protection device of FIGS. 18 and 19 with a first emitter/baseSTI spacing distance.

FIG. 28 is a partial sectional side elevation view of another example ofthe NPN ESD protection device of FIGS. 18 and 19 with a smaller secondemitter/base STI spacing distance.

FIG. 29 is a graph that shows comparative current/voltage curves for theNPN ESD protection devices of FIGS. 27 and 28.

FIG. 30 is a schematic diagram of an integrated circuit with an ESDprotection device.

DETAILED DESCRIPTION

In the drawings, like reference numerals refer to like elementsthroughout, and the various features are not necessarily drawn to scale.One or more operational characteristics of various circuits, systemsand/or components are hereinafter described in the context of functionswhich in some cases result from configuration and/or interconnection ofvarious structures when circuitry is powered and operating.

FIGS. 1 and 2 show respective sectional side and top views of anintegrated circuit (IC) electronic device 100 with an SCR type ESDprotection device 101. The SCR 101 is schematically shown in thedrawings, and includes an anode labeled “A”, a cathode labeled “C”, anda gate labeled “G”. FIG. 2 shows the sectional top plan view of aportion of the SCR ESD protection device 101 taken along line 2-2 inFIG. 1, and FIG. 1 shows a partial sectional side view taken along line1-1 in FIG. 2. As shown in FIG. 1, the electronic device 100 includes anSOI structure with a semiconductor substrate 102 (e.g., silicon) havinga first (e.g., bottom) side and an opposite second (e.g., top) side. Inone example, the semiconductor substrate 102 is doped with n-typedopants, such as phosphorus (e.g., labeled “N+” in FIG. 1). The SOIstructure also includes an insulator layer 104, such as silicon dioxide(SiO₂) with opposite first and second (e.g., bottom and top) sides,where the bottom or first side of the insulator layer 104 is disposedalong the top or second side of the semiconductor substrate 102. Inaddition, the SOI structure includes an upper semiconductor layer 106(e.g., silicon), with opposite first and second (e.g., bottom and top)sides. The first side of the semiconductor layer 106 is disposed alongthe second side of the insulator layer 104. The resulting SOI structureincludes two semiconductor layers 102 and 106 separated by the insulatorlayer 104. The lower semiconductor substrate 102 can be used as a handleduring manufacturing and can be referred to as a handle substrate.

The electronic device 100 includes a multi-layer metallization structure108 that extends over or above the upper second side of thesemiconductor layer 106, as shown in FIG. 1. The SCR ESD protectiondevice 101 in this example is fabricated on and/or in the uppersemiconductor layer 106 in an active region 110 of the electronic device100. The active region 110 in one example is laterally surrounded onfour sides by an isolation region 112, although not a requirement of allpossible implementations. The ESD protection device 101 also includesone or more isolation layers, including various shallow trench isolation(STI) structures with an isolation layer 114 formed in a correspondingtrench in the upper second side of the semiconductor layer 106.

The ESD protection device 101 in FIGS. 1 and 2 is fabricated on and/orin the upper semiconductor layer 106 and includes a first implantedregion 116 and a second implanted region 118 disposed in thesemiconductor layer 106. The first implanted region 116 is disposedalong a first portion of the upper second side of the semiconductorlayer 106 and includes majority carrier dopants of a first type (e.g.,P, such as boron). The second implanted region 118 is disposed along asecond portion of the second side of the semiconductor layer 106 and islaterally spaced apart from the first implanted region 116 along a firstdirection (e.g., the “X” direction in FIGS. 1 and 2). The secondimplanted region 118 includes majority carrier dopants of a differentsecond type (e.g., N, such as phosphorus). The ESD protection device 101has a finger or “racetrack” shape, as shown in FIG. 2, where the secondimplanted region 118 is located at a center position, and the firstimplanted region 116 laterally surrounds the center position. Although asingle finger shape is shown, different implementations can include morethan one finger shape, formed generally parallel and spaced from oneanother along the first direction X.

The ESD protection device 101 in FIG. 1 also includes a third implantedregion 120 disposed along a third portion of the upper second side ofthe semiconductor layer 106. The third implanted region 120 extendsalong the first direction X from the first implanted region 116 to thesecond implanted region 118. The third implanted region 120 includesmajority carrier dopants of the second type N. In one example, theelectronic device 100 is an integrated circuit with other electroniccomponents fabricated on and/or in other regions of the SOI structure(not shown), including field effect transistors (FETs) with implantedsource and drain regions. In this example, the FET source and drainfeatures are concurrently formed with the corresponding ones of therespective first and second implanted regions 116 and 118 of the SCR ESDprotection device 101. In this example, moreover, the FET devices mayinclude lightly doped drain (LDD) implanted regions that areconcurrently implanted with the third implanted region 120 of the SCRESD protection device 101.

In one example, the LDD regions and the third implanted region 120includes n-type majority carrier dopants (e.g., phosphorus) at a dopantconcentration of 5×10¹⁵ cm⁻³ to 1×10¹⁷ cm⁻³ at or near the top of theregion 120 beneath the STI isolation layer 114 to provide a drift region122 between the respective first and second implanted regions 116 and118. In one example, for a breakdown voltage rating of 100 V or more forthe SCR ESD protection device 101, the n-type carrier concentration ofthe third implanted region 120 is about 2×10¹⁶ cm⁻³ at or near the topof the region 120 beneath the STI isolation layer 114. In certainimplementations, increasing the dopant concentration can accommodateincreased field plate/isolation layer overlap distances to facilitatereduced breakdown voltage variation for an ESD protection device 101. Inone example, the third implanted region 120 has an implanted depth belowthe STI isolation layer 114 along a second direction (e.g., downwardalong the “Z” direction in FIG. 1) from 3 μm to 16 μm, such as 6-7 μm,for a 100 V breakdown voltage rating of the ESD protection device 101.The first and second directions X and Z are orthogonal to one anotherand are both orthogonal to a third direction “Y” shown in FIG. 2.

The SCR ESD protection device 101 in FIG. 1 includes a first isolationlayer 114 that extends in a corresponding trench in the second side ofthe semiconductor layer 106 along the first direction X from a portionof the first implanted region 116 inward over the third implanted region120 to a portion of the second implanted region 118.

The SCR ESD protection device 101 in this example forms an N-P-N-Pstructure to provide terminals of the SCR, including implanted portions124 and 126 of the first implanted region 116 and implanted portions 128and 129 of the second implanted region 118. The SCR cathode C includes afirst implanted portion 126 of the first implanted region 116. The firstimplanted portion 126 of the first implanted region 116 includesmajority carrier dopants of the second type N at a dopant concentrationgreater than a dopant concentration of a remainder of the firstimplanted region 116 (e.g., labeled “N+” in FIG. 1). The SCR gate Gincludes a second implanted portion 124 of the first implanted region116. The second implanted portion 124 includes majority carrier dopantsof the first type P at a dopant concentration greater than the dopantconcentration of the remainder of the first implanted region 116 (e.g.,labeled “P+”).

The SCR anode A includes the implanted portion 128 of the secondimplanted region 118. The implanted portion 128 includes majoritycarrier dopants of the first type P at a dopant concentration greaterthan a dopant concentration of a remainder of the second implantedregion 118 (e.g., labeled “P+”). The implanted portion 129 of the secondimplanted region 118 includes N type majority carrier dopants at adopant concentration greater than a dopant concentration of theremainder of the second implanted region 118 (e.g., labeled “N+”).

The ESD protection device 101 also includes a conductive field plate 130disposed over part of the second side of the semiconductor layer 106. Inone example, the conductive field plate 130 is or includes polysilicon,which can be doped with impurities in one implementation. The conductivefield plate 130 extends along the first direction X over a portion ofthe first implanted region 116 from the first implanted portion 126thereof, past the first implanted region 116 and over a portion of theisolation layer 114. The conductive field plate 130 extends over aportion of the isolation layer 114 by a non-zero overlap distance 131.The first isolation layer 114 has a thickness 132 along the seconddirection Z, such as about 0.6 μm in one example. The overlap distance131 is 3.5 to 5.0 times the isolation layer thickness 132. The ESDprotection device 101 in FIGS. 1 and 2 also includes a second isolationlayer 114 that extends in a corresponding second trench in the secondside of the semiconductor layer 106 in the first implanted region 116.The second isolation layer 114 is laterally spaced apart from the firstisolation layer 114 and has a length 133 along the first direction X inFIG. 1 of 4 μm to 8 μm. For example, the second isolation layer 114 mayextend in the X-Y plane (e.g., around the finger shape in FIG. 2) fromimplanted portion 124 to implanted portion 126 with a length 133 of 4 μmto 8 μm.

In one example, the overlap distance 131 is 2.2 to 3.0 μm, the isolationlayer thickness 132 is 0.6 μm, the n-type majority carrier concentrationof the third implanted region 120 is about 2×10¹⁶ cm⁻³ at or near thetop of the region 120 beneath the STI isolation layer 114, and theimplanted depth of the third implanted region 120 below the STIisolation layer 114 along the second direction Z is in a range from 3 μmto 16 μm, such as 6-7 μm, for a 100 V breakdown voltage rating of theESD protection device 101. As discussed below in connection with FIGS.20-24, the relative sizes of the overlap distance 131, the isolationlayer thickness 132, and the dopant concentration of the third implantedregion 120 are tailored in ratiometric fashion to control (e.g.,mitigate) breakdown voltage variation with handle substrate biasing inoperation of the ESD protection device 101, wherein controlling theratio of the overlap distance 131 to the isolation layer thickness 132in a range of 3.5 to 5.0 provides benefits in terms of breakdown voltagestability for the electronic device 100. In another example, for anisolation layer thickness 132 of 0.6 μm and a nominal breakdown voltageof around 100 V (e.g., +/−2 V), the overlap distance 131 is in a rangeof 2.2 μm to 3.0 μm (e.g., the ratio of the overlap distance 131 to theisolation layer thickness 132 is in a range of 3.67 to 5.00).

The multi-layer metallization structure 108 in the electronic device 100includes conductive structures that electrically connect the cathode Cand the gate G of the SCR 101 to one another. This provides an ESDprotection device 101 that can be triggered by an ESD event that causesa voltage of a protected node of the device 100 to exceed a givendesigned breakdown voltage level. In one example described below inconnection with FIG. 30, the ESD protection device 101 is connected to aprotected pad (e.g., externally accessible pin, lead, etc.) of an ICelectronic device to protect an internal circuit from ESD eventsassociated with the protected pad. The example metallization structure108 in FIG. 1 includes a first level 140 with a pre-metal dielectric(PMD) material layer 141 (e.g., SiO₂), with conductive (e.g., tungsten,aluminum, copper, etc.) contacts 142 at select locations to provideelectrical connection to the implanted portions 124, 126, 128 and 129for selective interconnection of the terminals of the ESD protectiondevice 101. The metallization structure 108 includes a second level 150,with an inter-level or inter-layer dielectric (ILD) material layer 151(e.g., SiO₂) and conductive features 152 (e.g., copper, aluminum, etc.),as well as a third level 160 with an associated ILD layer 161 andconductive features 162, and a final level 170 with an ILD layer 171 andconductive features 172.

The sectional top view of FIG. 2 illustrates an example of the racetrackor finger shape, for a single finger example of the SCR ESD protectiondevice 101. In the illustrated example, the finger shape includes afirst (e.g., upper) end and an opposite second (e.g., lower) spaced fromone another along the third direction Y. The finger shape includes astraight portion 200 that extends along the third direction Y, as wellas a first (e.g., upper) turn portion 201 at the first end of the fingershape, and a second (e.g., lower) turn portion 202 at the second end ofthe finger shape. In this example, the first implanted region 116 andthe second implanted region 118 extend in the straight portion 200, aswell as around the first and second turn portions 201 and 202,respectively. Extending the first and second implanted regions 116 and118 around the turn portions 201 and 202 provides improved ESD currentcarrying capability for the SCR ESD protection device 101 and mitigatesESD current carrying capability variations even in the presence ofhandle substrate biasing during operation of the electronic device 100.Similar racetrack or finger-shaped structure enhancements can be used inother implementations, such as the PNP bipolar transistor ESD protectiondevice example in FIGS. 16 and 17 below, as well as in the NPN bipolartransistor ESD protection device example in FIGS. 18 and 19 below.

In the example electronic device 100 of FIGS. 1 and 2, the SCR ESDprotection device 101 is fabricated on and/or in the upper SOIsemiconductor layer 106, which affects the voltage potentialdistribution inside the ESD protection device 101 and its breakdownvoltage. The conductive field plate 130 can counteract the bottomsubstrate biasing effect and reduce/eliminate handle substrate effectson the breakdown voltage of the ESD protection device 101. In addition,the example SCR ESD protection device 101 includes the second isolationlayer (e.g., STI) between the gate and cathode implanted portions 124and 126 in the first implanted region 116, which helps control latch-upby increasing the gate resistance and improve the breakdown voltagestability and enhance the ESD current carrying capability with respectto handle substrate biasing effects.

Referring now to FIGS. 3-15, FIG. 3 shows a method 300 for fabricatingan electronic device, such as an IC with an ESD protection device. FIGS.4-15 show the electronic device 100 of FIGS. 1 and 2 and the SCR ESDprotection device 101 at different stages of fabrication according tothe method 300 of FIG. 3. In other examples, the method 300 can beimplemented to fabricate ICs or other electronic devices with PNP, NPNor other types of ESD protection devices, such as those in FIGS. 16-19below. The method 300 shows acts and events associated with constructionof the example SCR ESD protection device 101, and these steps mayconcurrently be used for fabricating other electronic circuits and/orcomponents (e.g., transistor circuits, etc.) in a single IC with the ESDprotection device 101, and a metallization structure (e.g., themetallization structure 108 in FIG. 1) can be constructed according tothe method 300 to connect one or more terminals of the ESD protectiondevice 101 to a protected circuit of the IC (not shown).

The method 300 includes providing a starting SOI substrate at 302 inFIG. 3. In one example, a p-doped silicon handle substrate 102 and aninsulator (e.g., SiO₂) layer 104 is provided at 302. FIG. 4 shows anexample starting SOI substrate 102, 104 including a prospective activeregion 110 and a surrounding isolation region 112. Similar processing isshown for the active region 110 and the isolation region 112 in FIGS.4-15. In other examples, different processing is used to form anisolation barrier in the region 112 that surrounds the active region110, for example, forming deep trench isolation structures and/ordifferent doping in the isolation region 112 to electrically isolatecircuitry of the active region 110, or portions thereof, from othercircuits outside the active region 110.

The example handle substrate 102 is or includes silicon with p-typedopants (e.g., boron), but other semiconductor materials or combinationsthereof can be used in other implementations. At 304, one or moreepitaxial layers are formed (e.g., deposited) on the upper second sideof the insulator layer 104. FIG. 4 shows one example, in which anepitaxial growth deposition process 400 is performed, which deposits theepitaxial silicon layer 106 on the upper second side of the insulatorlayer 104. The process 400 in one example forms n-doped epitaxialsilicon layer 106. In other example, a separate blanket implantationprocess 500 (FIG. 5) is performed at 306 in FIG. 3 to implant n-typedopants (e.g., phosphorus) into the epitaxial silicon layer 106. Variousimplantation steps and processes are used in the example method 300,some or all of which may include subsequent thermal processing, such asannealing to activate and diffuse implanted dopants. In addition, theplantation processes can be concurrently used for implanting features ofother circuitry (not shown), such as source and drain regions for fieldeffect transistors, including LDD implants to fabricate transistors orother circuitry outside the illustrated active region 110.

The method 300 continues at 308 with implanting n-type dopants to formSCR anode regions using a first mask. FIG. 6 shows one example, in whichan implantation process 600 is performed using a first implant mask 602.The process 600 in one example implants phosphorus or other n-typedopants into an exposed portion of the upper second side of thesemiconductor layer 106 to form the second implanted region 118 disposedalong a portion of the upper second side of the semiconductor layer 106.At 310 in FIG. 3, the method 300 continues with implanting p-dopants toform an SCR gate region using a second mask. FIG. 7 shows one example,in which an implantation process 700 is performed using an implantationmask 702. The implantation process 700 implants boron or other p-typedopants into an exposed portion of the upper second side of thesemiconductor layer 106 to form the first implanted region 116.

The method 300 continues at 312 with implanting n-type dopants to formthe third implanted region 120, for example, using a lightly doped drain(LDD) implantation and mask that are concurrently used elsewhere in theelectronic device 100 to form other circuits (not shown). FIG. 8 showsone example, in which a third implantation process 800 is performedusing a third implant mask 802, which implants phosphorus or othern-type dopants into the exposed region between the portions of the firstimplanted region 116. In this example, the implant mask 802 exposes thepreviously n-doped second implanted region 118, although the mask 802 inother examples covers the second implanted region 118. In anotherpossible implementation, the LDD implant is performed after formingpolysilicon structures (e.g., 316 and 318 described below).

In one example, the implantation process 800, and any subsequent thermalannealing process are tailored to control the final dopant concentrationof the third implanted region 120 to be tailored according to theoverlap distance 131 (e.g., FIG. 1) of the subsequently formedconductive field plate over a portion of the isolation layer 114, and tothe first isolation layer thickness 132. In one example, theimplantation process 800 in FIG. 8 forms the third implanted region 120with n-type majority carrier dopants (e.g., phosphorus) at a dopantconcentration of 5×10¹⁵ cm⁻³ to 1×10¹⁷ cm⁻³, such as about 2×10¹⁶ cm⁻³,at or near the top of the region 120 beneath the subsequently formed STIisolation layer 114 (e.g., FIG. 1 above) to provide a drift region 122between the respective first and second implanted regions 116 and 118.In one example, the implantation process 800 and any subsequentannealing create the third implanted region 120 with an implanted depthfrom 3 μm to 16 μm, such as 6-7 μm, below the bottom of the subsequentlyformed STI isolation layer.

The method 300 continues at 314 in FIG. 3 with a shallow trenchisolation processing to form shallow trench isolation layers (e.g., 114in FIG. 1). Other processes can be used, such as local oxidation ofsilicon (LOCOS) processing at 220 to form SiO₂ isolation layers 114.FIGS. 9-11 show one example of STI processing at 314. FIG. 9 shows anexample of STI trench formation, including performing an etch process900 with an etch mask 902. The etch process 900 in one example etchesthrough exposed portions of the upper second side of the semiconductorlayer 106 to form trenches 904 having a depth 132 tailored according toa design overlap distance 131 (e.g., FIG. 1) of the subsequently formedconductive field plate over a portion of the isolation layer 114 inorder to achieve a ratio of the overlap distance 131 to the isolationlayer thickness 132 in a range of 3.502 5.0, such as 3.67 to 5.00. Inthe illustrated example, the etch process 900 is continued for acontrolled time in order to provide a trench depth 132 of approximately0.6 μm.

The trench etch mask 902 is then removed, and a blanket oxide depositionprocess 1000 is performed in FIG. 10 to deposit SiO₂ or other suitableisolation material 114 in the etched trenches. FIG. 11 illustrates asubsequent planarization process 1100, such as chemical mechanicalpolishing (CMP) that removes excess portions of the deposited isolationmaterial 114, to leave the finished STI isolation structures 114. Asfurther shown in FIG. 11, the SCR implementation of FIGS. 1, 2 and 4-15provides the second isolation layer having a lateral width 133 along thefirst direction X, where the trench etch mask 902 in FIG. 9 includesopenings tailored to achieve the isolation layer width 133 for theisolation layer 114 within the first implanted region 116. The isolationlayers 114 may, but need not, have an upper surface that is generallycoplanar with the upper second surface of the semiconductor layer 106.

The method 300 continues at 316 and 318 in FIG. 3 with polysiliconprocessing to form a field plate structures (e.g., the conductive fieldplate 130 in FIG. 1 above). At 316, polysilicon is deposited, forexample, using a blanket polysilicon deposition process 1200 and FIG. 12that deposits polysilicon material 130 over the STI isolation layers 114and the remaining exposed upper second side of the semiconductor layer106. The polysilicon formation processing in FIG. 12 can include dopingthe deposited polysilicon to control the conductivity thereof. Thedeposited polysilicon is patterned at 318 in FIG. 3 to form the fieldplate structure. FIG. 13 shows one example, in which an etch process1300 is performed using an etch mask 1302 to remove depositedpolysilicon from the exposed portions of the isolation layers 114 andthe remaining exposed upper second side of the semiconductor layer 106.The etch mask 1302 is then removed, to leave the patterned conductivepolysilicon field plate 130.

The method 300 continues at 320 in FIG. 3 with implanting n-type dopantsto form heavily doped SCR anode and cathode contact implanted portions.FIG. 14 shows one example, in which an implantation process 1400 isperformed with an implantation mask 1402. The implantation process 1400implants phosphorus or other n-type dopants to form the implantedportion 126 of the first implanted region 116 and the implanted portion129 of the second implanted region 118 (e.g., labeled N+ in FIG. 14).The process 1400 implants the n-type dopants to form the implantedportions 126 and 129 having higher dopant concentrations and theassociated first and second implanted regions 116 and 118, respectively.

At 322 in FIG. 3, the method 300 continues with implanting p-dopants toform the P+ SCR anode and gate contacts. FIG. 15 shows one example, inwhich an implantation process 1500 is performed with an implantationmask 1502. The implantation process 1500 in this example implants boronor other p-type dopants to form the implanted portion 124 of the firstimplanted region 116 and the implanted portion 128 of the secondimplanted region 118 (labeled P+ in FIG. 15). The method 300 alsoincludes back end processing, such as metallization processing at 324 toform contacts and metallization structures (e.g., the multi-levelmetallization structure 108 in FIG. 1 above). The method 300 alsoincludes die singulation or separation at 326 in FIG. 3, and packagingat 328 in order to provide a packaged electronic device, such as an IC.

FIGS. 16 and 17 show another example electronic device 1600 thatincludes a PNP bipolar transistor-type ESD protection device 1601. Theelectronic device 1600 in FIGS. 16 and 17 includes structures, nodes,features, regions, dimensions, and materials 1602, 1604, 1606, 1608,1610, 1612, 1614, 1616, 1618, 1620, 1622, 1624, 1629, 1630, 1631, 1632,1640, 1641, 1642, 1650, 1651, 1652, 1660, 1661, 1662, 1670, 1671, and1672, that generally correspond to the respective structures, nodes,features, regions, dimensions, and materials 102, 104, 106, 108, 110,112, 114, 11, 118, 120, 122, 124, 129, 130, 131, 132, 140, 141, 142,150, 151, 152, 160, 161, 162, 170, 171, and 172 of the electronic device100 as described in connection with FIGS. 1 and 2 above. FIG. 16 shows apartial sectional side elevation view the electronic device 1600 takenalong line 16-16 in FIG. 17, and FIG. 17 shows a partial sectional topplan view of the electronic device 1600 taken along line 17-17 in FIG.16, including the PMD layer contacts 1642.

In this example, the ESD protection device 1601 is a PNP transistor 1601with a collector C that includes the implanted portion 1624 of the firstimplanted region 1616. The implanted portion 1626 of the first implantedregion 1616 includes p-type majority carrier dopants (e.g., boron, etc)at a dopant concentration greater than the dopant concentration of theremainder of the first implanted region 1616. The PNP ESD protectiondevice 1601 in FIGS. 16 and 17 also includes a base B that includes theimplanted portion 1629 of the second implanted region 1618, where theimplanted portion 1629 includes n-type majority carrier dopants (e.g.,phosphorus, etc.) at a dopant concentration greater than the dopantconcentration of a remainder of the second implanted region 1618. ThePNP ESD protection device 1601 also has an emitter E that includes theimplanted portion 1624 of the third implanted region 1620. The implantedportion 1624 of the third implanted region 1620 includes p-type majoritycarrier dopants at a dopant concentration greater than the dopantconcentration of a remainder of the third implanted region 1620. Themetallization structure 1608 in this example includes conductivestructures 1642, 1652, 1662, 1672 that electrically connect the emitterE and the base B of the PNP transistor ESD protection device 1601 to oneanother.

The PNP ESD protection device 1601 is fabricated on and/or in the uppersecond side of the of the N semiconductor layer 1606 which affects thevoltage potential distribution inside the device 1600 and its breakdown.The conductive field plate 1630 with tailored overlap distance 1631counteracts the bottom substrate bias effect and reduces or mitigatesthe variation in the breakdown voltage. In addition, the STI isolationlayer 114 formed between the base and emitter helps control latch-up byincreasing the base resistance. In this regard, like the device 100above (and the NPN example in FIGS. 18 and 19 below), the use of therecessed first STI layer 1614 between the emitter and base in the PNPdevice 1601 is more effective in controlling the base resistance Rb thanjust spacing. In addition, the illustrated example ESD protectiondevices, whether SCR, PNP or NPN, use finger or racetrack configurationsor shapes, whether single finger shapes, or multi-finger arrangements.FIG. 17 shows the finger shape for the example PNP ESD protection device1601, that includes a straight portion 1700 that extends along the thirddirection Y, as well as a first (e.g., upper) turn portion 1701 at thefirst end of the finger shape, and a second (e.g., lower) turn portion1702 at the second end of the finger shape. Like the SCR example inFIGS. 1 and 2 above (and the NPN example in FIGS. 18 and 19 below), thefirst implanted region 1616 and the second implanted region 1618 extendin the straight portion 1700, as well as around the respective first andsecond turn portions 1701 and 1702. This feature facilitates uniformbase resistance Rb in the corners, which in turn improves the ESDcurrent handling capability, for example, by a factor of 10 in theillustrated implementations.

FIGS. 18 and 19 show another example electronic device 1800 thatincludes an NPN bipolar transistor-type ESD protection device 1601. Theelectronic device 1800 in FIGS. 16 and 17 includes structures, nodes,features, regions, dimensions, and materials 1802, 1804, 1806, 1808,1810, 1812, 1814, 1816, 1818, 1820, 1822, 1824, 1826, 1829, 1830, 1831,1832, 1840, 1841, 1842, 1850, 1851, 1852, 1860, 1861, 1862, 1870, 1871,and 1872, that generally correspond to the respective structures, nodes,features, regions, dimensions, and materials 102, 104, 106, 108, 110,112, 114, 11, 118, 120, 122, 124, 126, 129, 130, 131, 132, 140, 141,142, 150, 151, 152, 160, 161, 162, 170, 171, and 172 of the electronicdevice 100 as described in connection with FIGS. 1 and 2 above. FIG. 18shows a partial sectional side elevation view the electronic device 1800taken along line 18-18 in FIG. 19, and FIG. 19 shows a partial sectionaltop plan view of the electronic device 1800 taken along line 19-19 inFIG. 18, including the PMD layer contacts 1842.

The NPN ESD protection device 1801 in FIGS. 18 and 19 has an emitter Ethat includes a first implanted portion 1826 of the first implantedregion 1816. The first implanted portion 1826 includes n-type majoritycarrier dopants at a dopant concentration greater than the dopantconcentration of a remainder of the first implanted region 1816. The ESDprotection device 1801 also has a base B with a second implanted portion1824 of the first implanted region 1816, where the second implantedportion 1824 includes p-type majority carrier dopants at a dopantconcentration greater than the dopant concentration of the remainder ofthe first implanted region 1816. This example also has an NPN transistorcollector C with an implanted portion 1829 of the second implantedregion 1818. The implanted portion 1829 includes n-type majority carrierdopants at a dopant concentration greater than the dopant concentrationof the remainder of the second implanted region 1818. The NPN ESDprotection device 1801 in this example also includes a second isolationlayer 1814 disposed between the emitter E and the base B along the firstdirection X. In addition, the metallization structure 1808 of theelectronic device 1800 in FIGS. 18 and 19 includes conductive structures1842, 1852, 1862, 1872 that electrically connect the emitter E and thebase B of the NPN transistor 1801 to one another.

Like the SCR and PNP examples above, the NPN ESD protection device 1801in FIGS. 18 and 19 is fabricated on and/or in the upper second side ofthe of the N semiconductor layer 1806 which affects the voltagepotential distribution inside the device 1800 and its breakdown. Theconductive field plate 1830 with tailored overlap distance 1831counteracts the bottom substrate bias effect and reduces or mitigatesthe variation in the breakdown voltage. In addition, the STI isolationlayer 1814 formed between the base and emitter helps control latch-up byincreasing the base resistance. In addition, the use of the recessedfirst STI layer 1814 between the emitter and base in the NPN device 1801is more effective in controlling the base resistance Rb than justspacing. The NPN ESD protection device 1801 in certain examples alsouses single or multiple finger shapes, as shown in FIG. 19, including astraight portion 1900 extending along the Y direction, a first (e.g.,upper) turn portion 1901 at the first end of the finger shape, and asecond (e.g., lower) turn portion 1902 at the second end of the fingershape. Like the SCR and PNP examples above, the first implanted region1816 and the second implanted region 1818 extend in the straight portion1900, as well as around the respective first and second turn portions1901 and 1902 to facilitate uniform base resistance Rb in the corners,and to improve the ESD current handling capability.

FIG. 20 shows a graph 2000 with two sets of comparative center and edgevoltage-current (V-I) curves that illustrate handle substrate biaseffect on ESD protection device breakdown voltage. The graph 2000 showsa first set of curves 2002 corresponding to ESD protection devicecurrent as a function of voltage for zero handle substrate bias voltage(e.g., V_(SUB)=0 V), including a curve 2004 showing the device currentat the center of the finger structure, and a curve 2006 showing thedevice current at the edge of the finger structure. In this example, thecenter of the device breaks down before the edge, and the actualbreakdown voltage is shown in the graph 2000 as a first breakdownvoltage BV1.

FIG. 20 also shows a second set of curves 2012 corresponding to the ESDprotection device current for a non-zero substrate voltage near therated breakdown voltage of the device (e.g., V_(SUB)=100 V for a devicewith a rated breakdown voltage of 100 V). The second set of curves 2012includes a curve 2014 showing the device current at the center of thefinger structure, and a curve 2016 showing the device current at theedge of the finger structure. The center of the substrate biased ESDprotection device also breaks down before the edge, and the breakdownvoltage is shown as a second breakdown voltage BV2.

FIG. 20 illustrates the difference between the two breakdown voltages(e.g., BV1−BV2) as the resulting breakdown voltage variation 2020(labeled ΔBV). The graph 2000 shows that the handle substrate biasvoltage condition affects the ESD protection device breakdown voltage.In the illustrated example, changing the handle substrate bias V_(SUB)from 0 V to 100 V changes the breakdown voltage from the initial levelBV1=100 V to the lowered second level BV2=80-85 V, for an examplebreakdown voltage variation 2020 (ΔBV=10-15 V).

Referring also to FIGS. 21-24, the features of the example SCR, PNP andNPN ESD protection devices 101, 1601 and 1801, including the control ofthe relative sizing of the field plate/isolation layer overlap distance(e.g., 131, 1631, 1831) and the isolation layer thickness (e.g., 132,1632, 1832). These features can be used to control the breakdown voltagevariation 2020 for a given ESD protection device (e.g., 101, 1601 and/or1801 above), and the breakdown voltage variation 2020 can be furtherreduced for a given design by selecting the dopant concentration of thethird implanted regions (e.g., 120, 1620, 1820) as described above.These features can be employed to advantageously reduce the breakdownvoltage variation as a function of the handle substrate bias voltage.

FIGS. 21-24 show the advantages of tailoring the field plate/isolationlayer overlap distance (e.g., 131, 1631, 1831 above) according to theisolation layer thickness (e.g., 132, 1632, 1832). FIGS. 21-24 show highvoltage ESD event electric potential field line simulations forprogressively increased field plate/isolation layer overlap distance1632 for different implementations of the example PNP ESD protectiondevice 1601 of FIGS. 16 and 17 with a constant isolation layer (e.g.,STI) thickness 1632 of approximately 0.6 μm (e.g., region 1620 in FIG.16 above), the same third implanted region depth of 6 to 7 μm, and thesame third implanted region dopant concentration of about 2×10¹⁶ cm⁻³ ator near the top of the region 1620 beneath the STI isolation layer 1614(FIG. 16).

FIGS. 21 and 22 show example simulated electric field lines inrespective unbiased and a biased handle substrate conditions for a PNPESD protection device 1601. In FIG. 21, the handle substrate bias of thesemiconductor substrate 1602 V_(SUB)=0 V, and the overlap distance 1631of the field plate 1630 over the STI insulation layer 1614 is 1.2 μm.FIG. 21 shows example equal potential lines 2100 in a range from a firstline 2101 at 0 V to a final line 2102 at 130.5 V, with the lines 2100showing the field distribution within a portion of the ESD protectiondevice 1601 for the unbiased handle substrate condition, resulting in asimulated breakdown voltage of 130 V. FIG. 22 shows equal potentiallines 2200 for the same ESD protection device 1601 with a thickness 1632of 0.6 μm and an overlap distance 1631 of 1.2 μm, with a handlesubstrate bias of the semiconductor substrate 1602 V_(SUB)=100 V. Theset of equal potential lines 2200 in FIG. 22 includes an example firstline 2101 corresponding to 0 V, and a final line 2202 corresponding to130.5 V. At this handle substrate bias level, the device 1601 has abreakdown voltage of 118 V, and the breakdown voltage variation ΔBV=12V.

FIGS. 23 and 24 show further example simulated electric field lines inrespective unbiased and a biased handle substrate conditions for amodified PNP ESD protection device 1601 with the overlap distance 1631increased to 2.0 μm, and all other associated dimensions and dopantconcentrations the same as in the simulations of FIGS. 21 and 22 above.FIG. 23 shows the unbiased condition where the handle substrate bias ofthe semiconductor substrate 1602 V_(SUB)=0 V, and illustrates simulatedequal potential lines 2300 in a range from a first line 2301 at 0 V to afinal line 2302 at 130.5 V in a portion of the ESD protection device1601 for the unbiased handle substrate condition, resulting in asimulated breakdown voltage of 130 V. For the biased condition, FIG. 24shows a set of equal potential lines 2400 for the same ESD protectiondevice 1601 with a handle substrate bias of the semiconductor substrate1602 V_(SUB)=100 V, including a first line 2401 corresponding to 0 V,and a final line 2402 corresponding to 130.5 V. At this handle substratebias in condition, the device 1601 has a breakdown voltage of 126 V, andthe significantly reduced breakdown voltage variation ΔBV=4 V. FIGS.21-24, the control of the relative dimensions 1631 and 1632 can mitigatethe breakdown voltage variation ΔBV to facilitate use of predictable ESDprotection in integrated circuits or other electronic devices.

FIGS. 25 and 26 show further examples of tailoring the overlap distance1631 of the field plate 1830 over the STI insulation layer 1614 indifferent implementations of the PNP ESD protection device 1601 of FIGS.16 and 17. FIG. 25 shows a set of electric field strength regions 2500,including a first region 2501 corresponding to an electric fieldstrength of 1×10⁵ V/cm and a final region 2502 corresponding to anelectric field strength of 5.5×10⁵ V/cm for an overlap distance 1631 of2.0 μm at a handle substrate bias voltage of 100 V, which results in abreakdown voltage variation ΔBV=4 V compared with an unbiased handlesubstrate. FIG. 26 shows a set of electric field strength regions 2600,including a first region 2601 corresponding to an electric fieldstrength of 1×10⁵ V/cm and a final region 2602 corresponding to anelectric field strength of 5.5×10⁵ V/cm for an increased fieldplate/insulation layer overlap distance 1631 of 2.4 μm at a handlesubstrate bias voltage of V_(SUB)=100 V. The increased overlap distance1631 in this example results in a reduced breakdown voltage variationΔBV=3 V compared with an unbiased handle substrate.

Referring also to FIGS. 27-29, FIGS. 27 and 28 show example simulatedelectric fields in a portion of the NPN ESD protection device 1801 ofFIGS. 18 and 19 above for two different values of the emitter/base STIspacing distance (e.g., the lateral length 1833 of the second isolationlayer 1814 in FIG. 18 above). The NPN ESD protection device 1801 of FIG.27 is implemented with a first emitter/base STI spacing distance 2700 of4 μm. The implementation of the ESD protection device 1801 in FIG. 28has a smaller second emitter/base STI spacing distance 2800 of 1 μm.FIG. 29 shows a graph 2900, including comparative current/voltage curvesfor the NPN ESD protection devices of FIGS. 27 and 28. The first curve2901 corresponds to the snap-back performance of the NPN ESD protectiondevice 1801 of FIG. 27 with the emitter/base STI spacing distance 2700of 4 μm, and the second curve 2902 shows the snap-back performance ofthe NPN ESD protection device 1801 of FIG. 28 with the shortenedemitter/base STI spacing distance 2700 of 1 μm. The example simulationsof FIGS. 27-29 show that the ESD protection device snap-back can beadjusted by design of the spacing distance 1831 in FIG. 18 (e.g., andthe second insulation layer lateral distance 131 in the SCR ESDprotection device 101 of FIG. 1 above). The distances 131 and 1831 canbe set to suitable values to shorten the snap-back to facilitate higherESD current handling capability by improving the ability of the deviceto handle much higher current before thermal failure. In certainimplementations, the second insulation layer lateral distances 131 and1831 can be in the range of 4.0 μm to 8.0 μm.

FIG. 30 shows an example IC electronic device 3000 with an ESDprotection device as described above (e.g., and SCR ESD protectiondevice 101, a PNP ESD protection device 1601, and NPN ESD protectiondevice 1801, etc.). The IC 3000 also includes a protected circuit orcomponent 3001 connected between a protected pad 3002 (e.g., ICterminal, pin, pad, etc.) and an associated protected internal node 3004and a reference voltage (e.g., GND). The IC 3000 also includes a powerpad 3006 (e.g., to receive a supply voltage VDD), and an internal node3008 connects the supply voltage from the power pad 3006 to theprotected circuit or component 3001. In this example, the protectedcircuit or component 3001 is connected between the protected pad 3002(e.g., the protected node 3004) and a reference node 3010 (GND), and theESD protection device 101, 1601, 1801 is connected in parallel with theprotected circuit or component 3001. In this example, the electronicdevice 3000 is an integrated circuit IC 3000 with the protected circuitor component 3001 connected to an externally accessible terminal or pad3002, and wherein the ESD protection device 101, 1601, 1801 iselectrically connected to the externally accessible terminal or pad 3002of the IC 3000. ESD protection device 101, 1601, 1801 protects thecircuit or component 3001 against ESD events associated with theexternally accessible electrically conductive pad structure 3002, forexample, when the protected pad is soldered to a host printed circuitboard (PCB) or otherwise subject to hot-plug surges, switching noise orother transient voltage conditions. In steady state operation, with asupply voltage provided to the VDD pad 3006, voltage levels at theprotected pad 3002 below the breakdown voltage rating of the ESDprotection device 101, 1601, 1801 will not trigger conduction by the ESDprotection device 101, 1601, 1801, and the protected circuit orcomponent 3001 operates in a normal designed fashion. If an ESD eventoccurs at the protected pad 3002, the associated pad voltage VPAD risesquickly, for example, with a rise time of approximately 10 ns or less ina 2000 V human body model (HBM) ESD test event, which causes voltagebreakdown within the ESD protection device 101, 1601, 1801, causing theESD event current to conduct through the protection device 101, 1601,1801, thereby preventing excessive current flow in the protected circuitor component 3001.

The above examples are merely illustrative of several possibleimplementations of various aspects of the present disclosure, whereinequivalent alterations and/or modifications will occur to others skilledin the art upon reading and understanding this specification and theannexed drawings. Modifications are possible in the described examples,and other implementations are possible, within the scope of the claims.

What is claimed is:
 1. An electronic device, comprising: asilicon-on-insulator (SOI) structure including a semiconductor layer;and an electrostatic discharge (ESD) protection device, including: afirst implanted region disposed in the semiconductor layer, the firstimplanted region including majority carrier dopants of a first type, asecond implanted region disposed in the semiconductor layer and spacedapart from the first implanted region along a first direction, thesecond implanted region including majority carrier dopants of a secondtype, a third implanted region disposed in the semiconductor layer, thethird implanted region extending along the first direction from thefirst implanted region to the second implanted region, the thirdimplanted region including majority carrier dopants of the second type,an isolation layer extending in a trench in the semiconductor layer, theisolation layer extending along the first direction from the firstimplanted region, and having a thickness along a second direction, thefirst and second directions being orthogonal to one another, and aconductive field plate disposed over the semiconductor layer, theconductive field plate extending along the first direction over aportion of the first implanted region, and extending past the firstimplanted region and over a portion of the isolation layer by an overlapdistance, the overlap distance being 3.5 to 5.0 times the thickness ofthe isolation layer.
 2. The electronic device of claim 1, wherein thethird implanted region includes majority carrier dopants of the secondtype at a dopant concentration of 5×10¹⁵ cm⁻³ to 1×10¹⁷ cm⁻³.
 3. Theelectronic device of claim 1, wherein the ESD protection device has afinger shape with first and second ends, the finger shape including: astraight portion extending along a third direction, the third directionbeing orthogonal to the first and second directions, a first turnportion at the first end of the finger shape, and a second turn portionat the second end of the finger shape; and wherein the first implantedregion and the second implanted region extend in the straight portionand in the first and second turn portions of the finger shape.
 4. Theelectronic device of claim 3, wherein the ESD protection device furtherincludes a second isolation layer extending in a second trench in thesemiconductor layer in the first implanted region and spaced apart fromthe isolation layer, the second isolation layer having a length alongthe first direction of 4 μm to 8 μm.
 5. The electronic device of claim4, wherein the ESD protection device is a silicon-controlled rectifier(SCR), the SCR comprising: a cathode, including a first implantedportion of the first implanted region, the first implanted portion ofthe first implanted region including majority carrier dopants of thesecond type at a dopant concentration greater than a dopantconcentration of a remainder of the first implanted region; a gate,including a second implanted portion of the first implanted region, thesecond implanted portion of the first implanted region includingmajority carrier dopants of the first type at a dopant concentrationgreater than a dopant concentration of the remainder of the firstimplanted region; and an anode, including an implanted portion of thesecond implanted region, the implanted portion of the second implantedregion including majority carrier dopants of the first type at a dopantconcentration greater than a dopant concentration of a remainder of thesecond implanted region; the electronic device further comprising ametallization structure, including conductive structures thatelectrically connect the cathode and the gate of the SCR to one another.6. The electronic device of claim 4, wherein the ESD protection deviceis an NPN transistor, the NPN transistor comprising: an emitter,including a first implanted portion of the first implanted region, thefirst implanted portion of the first implanted region including majoritycarrier dopants of the second type at a dopant concentration greaterthan a dopant concentration of a remainder of the first implantedregion; a base, including a second implanted portion of the firstimplanted region, the second implanted portion of the first implantedregion including majority carrier dopants of the first type at a dopantconcentration greater than a dopant concentration of the remainder ofthe first implanted region; and a collector, including an implantedportion of the second implanted region, the implanted portion of thesecond implanted region including majority carrier dopants of the secondtype at a dopant concentration greater than a dopant concentration of aremainder of the second implanted region; the second isolation layerbeing disposed between the emitter and the base of the NPN transistoralong the first direction; the electronic device further comprising ametallization structure, including conductive structures thatelectrically connect the emitter and the base of the NPN transistor toone another.
 7. The electronic device of claim 4, wherein the thirdimplanted region includes majority carrier dopants of the second type ata dopant concentration of 5×10¹⁵ cm⁻³ to 1×10¹⁷ cm⁻³.
 8. The electronicdevice of claim 1, wherein the ESD protection device further includes asecond isolation layer extending in a second trench in the second sideof the semiconductor layer in the first implanted region and spacedapart from the isolation layer, the second isolation layer having alength along the first direction of 4 μm to 8 μm.
 9. The electronicdevice of claim 8, wherein the ESD protection device is asilicon-controlled rectifier (SCR), the SCR comprising: a cathode,including a first implanted portion of the first implanted region, thefirst implanted portion of the first implanted region including majoritycarrier dopants of the second type at a dopant concentration greaterthan a dopant concentration of a remainder of the first implantedregion; a gate, including a second implanted portion of the firstimplanted region, the second implanted portion of the first implantedregion including majority carrier dopants of the first type at a dopantconcentration greater than a dopant concentration of the remainder ofthe first implanted region; and an anode, including an implanted portionof the second implanted region, the implanted portion of the secondimplanted region including majority carrier dopants of the first type ata dopant concentration greater than a dopant concentration of aremainder of the second implanted region; the electronic device furthercomprising a metallization structure, including conductive structuresthat electrically connect the cathode and the gate of the SCR to oneanother.
 10. The electronic device of claim 8, wherein the ESDprotection device is an NPN transistor, the NPN transistor comprising:an emitter, including a first implanted portion of the first implantedregion, the first implanted portion of the first implanted regionincluding majority carrier dopants of the second type at a dopantconcentration greater than a dopant concentration of a remainder of thefirst implanted region; a base, including a second implanted portion ofthe first implanted region, the second implanted portion of the firstimplanted region including majority carrier dopants of the first type ata dopant concentration greater than a dopant concentration of theremainder of the first implanted region; and a collector, including animplanted portion of the second implanted region, the implanted portionof the second implanted region including majority carrier dopants of thesecond type at a dopant concentration greater than a dopantconcentration of a remainder of the second implanted region; theelectronic device further comprising a metallization structure,including conductive structures that electrically connect the emitterand the base of the NPN transistor to one another.
 11. The electronicdevice of claim 1, wherein the electronic device is an integratedcircuit (IC), further including a protected circuit or componentconnected to an externally accessible terminal or pad of the IC, whereinthe ESD protection device is electrically connected to the externallyaccessible terminal or pad of the IC.
 12. The electronic device of claim1, wherein the conductive field plate includes polysilicon.
 13. Anelectronic device, comprising: a silicon-on-insulator (SOI) structureincluding a semiconductor layer; and an electrostatic discharge (ESD)protection device, including: a first implanted region disposed in thesemiconductor layer, the first implanted region including majoritycarrier dopants of a first type, a second implanted region disposed inthe semiconductor layer and spaced apart from the first implanted regionalong a first direction, the second implanted region including majoritycarrier dopants of a second type, a third implanted region disposed inthe semiconductor layer, the third implanted region extending along thefirst direction from the first implanted region to the second implantedregion, the third implanted region including majority carrier dopants ofthe second type, an isolation layer extending in a trench in thesemiconductor layer, the isolation layer extending along the firstdirection from the first implanted region, and having a thickness alonga second direction, the first and second directions being orthogonal toone another, and a conductive field plate disposed over thesemiconductor layer, the conductive field plate extending along thefirst direction over a portion of the first implanted region, andextending past the first implanted region and over a portion of theisolation layer by an overlap distance, the overlap distance being 3.5to 5.0 times the thickness of the isolation layer, wherein the ESDprotection device is a silicon-controlled rectifier (SCR), the SCRcomprising: a cathode, including a first implanted portion of the firstimplanted region, the first implanted portion of the first implantedregion including majority carrier dopants of the second type at a dopantconcentration greater than a dopant concentration of a remainder of thefirst implanted region; a gate, including a second implanted portion ofthe first implanted region, the second implanted portion of the firstimplanted region including majority carrier dopants of the first type ata dopant concentration greater than a dopant concentration of theremainder of the first implanted region; and an anode, including animplanted portion of the second implanted region, the implanted portionof the second implanted region including majority carrier dopants of thefirst type at a dopant concentration greater than a dopant concentrationof a remainder of the second implanted region; the electronic devicefurther comprising a metallization structure, including conductivestructures that electrically connect the cathode and the gate of the SCRto one another.
 14. An electronic device, comprising: asilicon-on-insulator (SOI) structure including a semiconductor layer;and an electrostatic discharge (ESD) protection device, including: afirst implanted region disposed in the semiconductor layer, the firstimplanted region including majority carrier dopants of a first type, asecond implanted region disposed in the semiconductor layer and spacedapart from the first implanted region along a first direction, thesecond implanted region including majority carrier dopants of a secondtype, a third implanted region disposed in the semiconductor layer, thethird implanted region extending along the first direction from thefirst implanted region to the second implanted region, the thirdimplanted region including majority carrier dopants of the second type,an isolation layer extending in a trench in the semiconductor layer, theisolation layer extending along the first direction from the firstimplanted region, and having a thickness along a second direction, thefirst and second directions being orthogonal to one another, and aconductive field plate disposed over the semiconductor layer, theconductive field plate extending along the first direction over aportion of the first implanted region, and extending past the firstimplanted region and over a portion of the isolation layer by an overlapdistance, the overlap distance being 3.5 to 5.0 times the thickness ofthe isolation layer, wherein the ESD protection device is an NPNtransistor, the NPN transistor comprising: an emitter, including a firstimplanted portion of the first implanted region, the first implantedportion of the first implanted region including majority carrier dopantsof the second type at a dopant concentration greater than a dopantconcentration of a remainder of the first implanted region; a base,including a second implanted portion of the first implanted region, thesecond implanted portion of the first implanted region includingmajority carrier dopants of the first type at a dopant concentrationgreater than a dopant concentration of the remainder of the firstimplanted region; and a collector, including an implanted portion of thesecond implanted region, the implanted portion of the second implantedregion including majority carrier dopants of the second type at a dopantconcentration greater than a dopant concentration of a remainder of thesecond implanted region; the electronic device further comprising ametallization structure, including conductive structures thatelectrically connect the emitter and the base of the NPN transistor toone another.
 15. An electronic device, comprising: asilicon-on-insulator (SOI) structure including a semiconductor layer;and an electrostatic discharge (ESD) protection device, including: afirst implanted region disposed in the semiconductor layer, the firstimplanted region including majority carrier dopants of a first type, asecond implanted region disposed in the semiconductor layer and spacedapart from the first implanted region along a first direction, thesecond implanted region including majority carrier dopants of a secondtype, a third implanted region disposed in the semiconductor layer, thethird implanted region extending along the first direction from thefirst implanted region to the second implanted region, the thirdimplanted region including majority carrier dopants of the second type,an isolation layer extending in a trench in the semiconductor layer, theisolation layer extending along the first direction from the firstimplanted region, and having a thickness along a second direction, thefirst and second directions being orthogonal to one another, and aconductive field plate disposed over the semiconductor layer, theconductive field plate extending along the first direction over aportion of the first implanted region, and extending past the firstimplanted region and over a portion of the isolation layer by an overlapdistance, the overlap distance being 3.5 to 5.0 times the thickness ofthe isolation layer, wherein the ESD protection device is a PNPtransistor, the PNP transistor comprising: a collector, including animplanted portion of the first implanted region, the implanted portionof the first implanted region including majority carrier dopants of thefirst type at a dopant concentration greater than a dopant concentrationof the remainder of the first implanted region; a base, including animplanted portion of the second implanted region, the implanted portionof the second implanted region including majority carrier dopants of thesecond type at a dopant concentration greater than a dopantconcentration of a remainder of the second implanted region; and anemitter, including an implanted portion of the third implanted region,the implanted portion of the third implanted region including majoritycarrier dopants of the first type at a dopant concentration greater thana dopant concentration of a remainder of the third implanted region; theelectronic device further comprising a metallization structure,including conductive structures that electrically connect the emitterand the base of the PNP transistor to one another.
 16. An electronicdevice, comprising: a silicon-on-insulator (SOI) structure, including: asemiconductor substrate, including opposite first and second sides, aninsulator layer, including opposite first and second sides, the firstside of the insulator layer disposed along the second side of thesemiconductor substrate, and a semiconductor layer, including oppositefirst and second sides, the first side of the semiconductor layerdisposed along the second side of the insulator layer; and anelectrostatic discharge (ESD) protection device, including: a firstimplanted region disposed along a first portion of the second side ofthe semiconductor layer, the first implanted region including majoritycarrier dopants of a first type, a second implanted region disposedalong a second portion of the second side of the semiconductor layer andspaced apart from the first implanted region along a first direction,the second implanted region including majority carrier dopants of asecond type, a third implanted region disposed along a third portion ofthe second side of the semiconductor layer, the third implanted regionextending along the first direction from the first implanted region tothe second implanted region, the third implanted region includingmajority carrier dopants of the second type, an isolation layerextending in a trench in the second side of the semiconductor layer, theisolation layer extending along the first direction from the firstimplanted region, and having a thickness along a second direction, thefirst and second directions being orthogonal to one another, and aconductive field plate disposed over part of the second side of thesemiconductor layer, the conductive field plate extending along thefirst direction over a portion of the first implanted region, andextending past the first implanted region and over a portion of theisolation layer; the ESD protection device having a finger shape withfirst and second ends, the finger shape including: a straight portionextending along a third direction, the third direction being orthogonalto the first and second directions, a first turn portion at the firstend of the finger shape, and a second turn portion at the second end ofthe finger shape; and the first implanted region and the secondimplanted region extending in the straight portion and in the first andsecond turn portions of the finger shape.
 17. The electronic device ofclaim 16, wherein the ESD protection device further includes a secondisolation layer extending in a second trench in the second side of thesemiconductor layer in the first implanted region and spaced apart fromthe isolation layer, the second isolation layer having a length alongthe first direction of 4 μm to 8 μm.
 18. The electronic device of claim16, wherein the electronic device is an integrated circuit (IC), furtherincluding a protected circuit or component connected to an externallyaccessible terminal or pad of the IC, wherein the ESD protection deviceis electrically connected to the externally accessible terminal or padof the IC.
 19. An electronic device, comprising: a silicon-on-insulator(SOI) structure, including a semiconductor layer; and an electrostaticdischarge (ESD) protection device, including: a first implanted regiondisposed in the semiconductor layer, the first implanted regionincluding majority carrier dopants of a first type, a second implantedregion disposed in the semiconductor layer and spaced apart from thefirst implanted region along a first direction, the second implantedregion including majority carrier dopants of a second type, a thirdimplanted region disposed in the semiconductor layer, the thirdimplanted region extending along the first direction from the firstimplanted region to the second implanted region, the third implantedregion including majority carrier dopants of the second type, a firstisolation layer extending in a trench in the semiconductor layer, thefirst isolation layer extending along the first direction from the firstimplanted region, and having a thickness along a second direction, thefirst and second directions being orthogonal to one another, aconductive field plate disposed over the semiconductor layer, theconductive field plate extending along the first direction over aportion of the first implanted region, and extending past the firstimplanted region and over a portion of the first isolation layer, and asecond isolation layer extending in a second trench in the semiconductorlayer in the first implanted region and spaced apart from the firstisolation layer, the second isolation layer extending from a firstimplanted portion of the first implanted region to a second implantedportion of the first implanted region, the first implanted portionincluding majority carrier dopants of the first type and the secondimplanted portion including majority carrier dopants of the second type.20. The electronic device of claim 19, wherein: the second isolationlayer has a length along the first direction of 4 μm to 8 μm; and theconductive field plate extends over the portion of the first isolationlayer by an overlap distance of 3.5 to 5.0 times the thickness of thefirst isolation layer.